In the field of arc welding, the main types of welding processes are gas-metal arc welding with solid (GMAW) or metal cored wires (GMAW-C), gas shielded flux-cored arc welding (FCAW-G), self-shielded flux-cored arc welding (FCAW-S), shielded metal arc welding (SMAW) and submerged arc welding (SAW).
Metal cored electrodes are used increasingly as an alternative to solid wires because of increased productivity during welding fabrication of structural components. Metal cored electrodes are composite electrodes consisting of a core (fill) material surrounded by a metallic outer sheath. The core consists mainly of iron powder and alloying and fluxing ingredients to help with arc stability, weld wetting and appearance etc., such that the desired appearance and mechanical properties are obtained in the weld. Metal cored electrodes are manufactured by mixing the ingredients of the core material and depositing them inside a formed strip, and then closing and drawing the strip to the final diameter. Metal cored electrodes provide increased deposition rates and produce a wider, more consistent weld penetration profile compared to solid electrodes. Moreover, they provide improved arc action, generate less fume and spatter, and provide weld deposits with better wetting compared to solid electrodes.
FCAW-S electrodes do not use any shielding during welding and protection of the weld metal from the ambient is achieved through the use of deoxidizers and dentriders like Al, Mg, Ti and Zr. However, a certain ratio of barium to lithium is often utilized in order to control the melting range and the fluidity of the slag and weld puddle. This ratio can be modified to render the electrode appropriate for welding out of position, i.e. either vertically up or vertically down. From ternary diagrams of barium, lithium and strontium fluorides, it is known that melting point is generally reduced with increasing levels of lithium fluoride.
Although electrodes with barium and lithium compounds are known, a need still remains for electrode and resulting slag compositions that exhibit improved properties, particularly with respect to the proportions of barium and lithium and the flow characteristics of the slag and weld puddle properties resulting therefrom.